I have both K/Ubuntu 9.10 (and 10.04 alpha 3) and openSuSE 11.2 installed.

Both are very robust and complete, but different approaches. OpenSuSE has many
built in tools whether you use the KDE or GNOME version. Ubuntu (GNOME) and
Kubuntu (KDE) use the default GNOME and KDE tools. Canonical has said that it
does this out of support to the respective projects. Mint has stepped into the
breach and filled this void by adding tools of its own for those who want them.
I don't see the need. You can't beat Synaptic for a package manager and I have
never had a need for networking help and some of the other things that Mint
offers.

Problems that I have with openSuSE (and I have used it from before Novell bought
them) are package management, stability, control over the boot process and lack
of applications. Yast (package manager) just plain sucks, IMO. I am not a big
fan of RPMs in general. SuSE is one of the easier distros for me to break and
that is saying something as I install lots of distros and applications. SuSE
does not pick up many of my partitions and drives and automatically make boot
entries in the boot loader. If you want lots of applications then Ubuntu wins
hands down.

However, openSuSE is a good choice for many people. It has a good community and
lots of help from the parent Novell.

I have installed just about every main distro and used them over periods of
years. I keep on coming back to K/Ubuntu (I write it this way because I use both
KDE and GNOME). It just offers the best experience for me. It is aggressively
developed, it is well supported, has a large and great community, it has lots of
resources such as forums, RSS feeds and podcasts devoted to it, it has the best
package format (DEB), it has the most applications and it works great on my
hardware. However, Linux users should try out lots and find what works for them.
It is all about freedom and choice.